v0.0.56

Changed

• Registry gained per-request memoization of get()/locate(), cleared on writes.
• Item registry identity is now scoped to the parent page: item UUIDs only need to be unique within their parent's collection field. Registry::SCHEMA bumped, forcing a reindex on upgrade.
• PageFiles' public-directory mirror sweep now lists the public directory once per page instead of once per file.

Fixed

• The admin page-tree partial could clobber a caller-passed $current_tree value; it now defaults it instead.